| 摘要 |
<p>The present invention relates to a lighting device using an LED, and more particularly, to an AC-driven LED lighting device with an improved modulation index (the modulation index is calculated using minimum and maximum values of an instantaneous light emission amount), which turns on an LED by using an instantaneous AC voltage periodically changing according to time. When an LED block does not directly receive a current from an AC power by adding a condenser in parallel to the LED block in which a current flow is controlled by a switch, the LED block receives a current from the condenser connected in parallel and is turned on. Therefore, the LED lighting device has an improved modulation index by preventing all LED blocks from being turned off at a time. Furthermore, it is possible to protect LEDs and achieve a high power factor by adopting a current source that restricts a source current.</p> |
